When electric field is applied across PN junction, the potential across the junction will be lowered to a value 0-V allowing the positive side of V to repel holes in the p-type material and the negative side of V to repel electrons in the N-type material. The flow of current across the junction itself is due to electron flow in the conduction band and hole flow in the valence band.

Hole flow and electron flows are equal at centre of the transition region.

When a diode is forward-biased, along with majority carrier that leads to large current, there is a small current set up due to minority carriers.